import java.util.*;

// a simple counter class
class Counter {
    private int value;
    
    public Counter() {
        value = 0;
    }

    public synchronized void increment() {
        int current_value = value;

        try {
            Thread.sleep(1);
        } catch (InterruptedException e) {

        }

        int new_value = current_value + 1;
        value = new_value;
    }

    public int getValue() {
        return value;
    }
}



// a thread class to increment a counter by a certain amount in parallel
class IncThread extends Thread {
    private Counter counter;
    private int amount;
    
    public IncThread(Counter c, int amt) {
        counter = c;
        amount = amt;
    }

    @Override
    public void run() {
        for (int i = 0; i < amount; i++) {
            counter.increment();
        }
    } 
}



public class Sharing2 {
    public static void main(String args[]) {
        // create a counter
        Counter counter = new Counter();

        // make some threads increment the counter
        IncThread [] threads = new IncThread[100];
        for (int i = 0; i < 100; i++) {
            threads[i] = new IncThread(counter, 5);
        }

        // start them all
        for (int i = 0; i < 100; i++) {
            threads[i].start();
        }

        // wait for them to finish
        try {
            for (int i = 0; i < 100; i++) {
                threads[i].join();
            }
        } catch (InterruptedException e) {

        }

        // get the value
        System.out.println(counter.getValue());
    }
}